Antifreeze composition



Y Patented Feb. 25, 1941 PATENT OFFICE- 2,233,185 ANTIFREEZE COMPOSITION David F. Smith, Snyder, N. Y.

N(; Drawing. Application January 21, 1938,

Serial No. 186,188

15 Claims.

This invention relates to improvements in antifreeze liquids of the type employed, for example, as heat transfer media with circulating systems.

One of the objects of this invention is to provide a liquid of this kind capable of efllcient use at very low temperatures, which is substantially non-corrosive of metals with which the solution may contact when in use. Another object of this invention is to provide a liquid of this kind comprising a solution of a readily soluble salt, which solution remains a free flowing liquid at very low temperatures, and which is substantially nonr corrosive of metals of the kind. commonly employed in connection with circulating systems for cooling or heating liquids.

It is also an object of this invention to provide a liquid of this kind including mainly an aqueous solution of an alkali metal salt of a fatty acid containing not more than nine carbon atoms per molecule. Still another object is to provide a liquid of this kind comprising mainly a solution of an alkali metal salt of a fatty acid having not more than nine carbon atoms per molecule,

in suflicient proportion to materially lower the freezing point of the liquid below that of water and with which certain corrosion inhibitors may be mixed.- It is also an object of this invention to provide a liquid comprising in the main a solution of an alkali metal salt of a fatty acid of this type, and with which may be used certainsubstances for reducing the wetting power or creeping tendency of the liquid in contact with metal and other solid surfaces. Another object is to provide an antifreeze liquid including a salt solution-of this kind in which an oil is miscible without requiring the usual emulsifying or wetting agent. 1

Another object of this invention is to provide a method of effecting heat transfer in a cooling system, which includes the circulation of a solution of an alkali metal salt of a fatty acid having not more than nine carbon atoms per molecule alkaline salt solution of this kind containing a material for decreasing the wetting power of the solution to metal and other solid surfaces.

Other objects of this invention will appear from the following description and claims. Solutions of certain salts of inorganic acids have heretofore been used in cooling systems of automobiles and while some of these salt mixtures have had no decidedly corrosive action upon iron, yet it has been found that they are very corrosive of aluminum and some other metals frequently employed in connection with circulating systems of internal combustion engines and the like, so that the use of such salt solutions had to be discontinued.

I have found that a very desirable antifreezing liquid can be produced by employing solutions of alkali metal salts of certain organic acids. I have found that the sodium and potassium salts of fatty acids containing not more than nine carbon atoms per molecule, when dissolved in sufllcient quantities of water to lower the freezing point of the solution materially below that of water, are substantially no more corrosive of metals than ordinary city water and have very desirable additional properties, namely, that solutions of some of these salts can be produced which can be readily circulated in ordinary circulation systems at temperatures of -50 C. and even lower, that the low temperature solubilities, for example, of potassium acetate, are high enough so that the increases in concentration normally occurring in practice will not cause separation of solid salt at low temperatures even in solutions having very low freezing points, and also that to these solutions can be added effective corrosion inhibitors. These solutions are also compatible with substances for reducing the wet- -ting power of the salt solutions to metal and other surfaces. I have also found that these salts, which in their pure states are often decidedly alkaline in reaction, may have their corrosion action in certain instances very materially reduced by rendering these solutions less alkaline, for example, by the addition of a suitable acid.

Potassium and sodium acetate, the corresponding formates, propionates, butyrates, and corresponding salts of other fatty acids'containlng not more than nine carbon atoms per molecule are very desirable for use in connection with liquids of this kind. Since solutions of any of these salts in their pure form are often decidedly alkaline in reaction, I may prefer to reduce the alkalinity of these solutions to avoid attack on metals, such for example, as aluminum. In order to prevent possible reactions in the solutions, I prefer to use for this purpose a suitable acid, for example, the acid of the salt in question,

although other acids may be employed, if desired, providing that they do not react with ingredients of my improved antifreezeliquidnor with the metals with which the liquidcontacts when in use. In order'to bufier these solutions so that they will resist any tendencyto change their pH value, a small amount of any of the common bufler mixtures may be added, for example, a small amount of boric acid mixed with its alkali metal salt, or an aikalimetal phosphate mixture, may be used. This makes it possible to maintain a solution substantially at a desired pH, even if the water used in diluting the solu tion is of alkaline or acid reaction.

The slightly alkaline salt solutions of this kind in any concentration do not attack 'metalsdetectably more than ordinary city water does and the salts are also very readily soluble in water, so that if all of the water of the solution is boiled off or evaporated, the residue can be readily dissolved in water, which is very desirable to free a circulating system of the residue, in the event that an antifreezing liquid becomes boiled down or evaporated to dryness.

In addition to the very desirable characteristics of being readily soluble in water and of being substantially non-corrosive of metals commonly employed in cooling systems, these solutions also have the desirable property of having solidifying points far below that of water. Aqueous solutions of these salts are miscible with alcohol,

glycerol and glycols, which'is a desirable feature.

in the event that my improved solution should be added to solutions of these materials. My improved solutions also have the advantagethat they can be sold in the form of concentrates and diluted for use by the addition of water thereto, 4

and furthermore, these solutions can be produced at lower cost than glycols and are far more stable than alcohols or glycols with respect to heat or oxidation or reduction.

Small quantities, for example from 4% to 1% of almost any of the well known corrosion inhibitors may be used in connection with solutions of these salts. Examples of corrosion inhibitors which may be used in connection with my antifreezing liquids are certain organic nitrogen compounds such as-urea and amino acridine derivatives. Arsenious oxide, chromates, such as sodium or potassium chromates, and potassium antimonyl tartrate may also be used.

I have also found that anti-pyrine constitutes an excellent inhibitor of corrosion, not only for use with my improved antifreeze solutions, but also for use with other solutions. This substance has the formula C11H12ON2, and has the peculiarity that in the same a nitrogen atom is a bonded to another nitrogen atom. Derivatives of anti-pyrine may also be used as'inhibitors of corrosion and the wordanti-pyrine as herein used is intended to include anti-pyrine and its derivatives. Small quantities of anti-pyrine may 4% of such material is used in the final solution so that the same will not, readily penetrate or seep through small leaks and so that the same will not tend to spread over solid surfaces. By

. way of examp1e,an animal, mineral or vegetable oil may be used.

One of the advantages of my improved antifreeze solution is that such 0118. may be readily .mixed withthe solution without the use of the usual wetting or emulsifying'agents. If foundv desirable in certain cases, wetting or emulsifyinx agents may be used. Such emulsifying or wetting agent-may be soap, an ethanolaminacal- 'cium oleate, magnesium 'oleatm-gum arabic or rosimor anyone ofa number ofwell known materials having a similar, action. Preferably mineral oil, such as a light petroleum oil, is usedonlyin conjunction with an approximately equal quantity of an animalor vegetable oil, or all or a part of the light mineral oil can be replaced by an oil of good dielectric properties'and high density, such for example as trichlor benzene, chlorinated diphenyl'or a phenyl ether. These high density oils can be. mixed in such proportions with the animal or vegetable oil as to obtain an oil mixture of the same density as the solution, thus forming a more stable emulsion. The use of an animal or vegetable oil which contains some free fatty acid may be desirable in some cases. In order to obtain the best results, the mixture of the water solution of the salt containing an emulsifying or wetting agent and oil may be passed. through a colloid mill to thoroughly homogenize the mixture, so that the oil and water will not separate out on standing, and 'so that emulsions with air will not be formed as when ordinary mixing its used. When a solution is prosuch solution will not cause trouble with the 18- nition system of an engine, partly because it collects in drops and does not creep over the surface, and partly because of the nonconducting properties of the oils. r

The addition of oils to the salt solution assists in protecting the metals against corrosion. Consequently, if a material of this kind is added to the solution to reduce the wetting power thereof to metal and other solid surfaces, it is frequently unnecessary to use an inhibitor of corrosion. Potassium acetate is very desirable for use in connection with liquids of this kind, since it very decidedly lowers the freezing or solidifying point r of the solution. I have found, for example, that if 3.0 pounds of potassium acetate are made up with water to a total volume of one gallon, the resulting solution will not freeze or solidify at a temperature above- 24 C., and it 5.0 pounds of this salt are made up with water to a total volume of one. gallon, the temperature may be lowered to about 55 0. without interfering with the free circulation of the solution. It should be pointed out in this connection that the freezing points of many of these solutions are somewhat indefinite and the temperatures here given represent the highest temperatures at which cloudiness appears in the solution, it being understood that the solutions do not in most cases by any means become entirely solid at these temperatures. Since commercial potassium acetate may have a pH value of about 10, I'may prefer to reduce the pH value to about 8 to 9 by adding anyorganicacid whose potassium salt will not be.

materially less soluble than potassium acetate.

Preferably acetic" acid is used for neutralizing potassium. acetate. This slightly alkaline salt solution, regardless of its concentration, will not. attack metals detectably more than city water does. If the water is boiled off or evaporated from the solution, the residue is in the form of a light fluil'y substance and not a compact solid and this substance is, consequently, readily penetrated by andquickly dissolved inwater and other mation of antifreezing solutions, which form hard compact masses when the solutions are evaporated to dryness. These compact masses are very hard to redissolve, especially when filling narrow passages. Potassium acetate is sufficiently soluble in water so that it can be marketed in the form of a concentrate containing 10 grams of commercial salt per 10 cc. of solution. This concentrated solution will not crystallize out until temperatures of about C. are reached, and hence the concentratedsolutions are practical for shipment and storage. If it is desired to lower the crystal point of, the concentrate, this may be done by adding small quantities of a1- cohol, acetone and other materials. For use in a circulating system, the concentrated solutions when diluted with equal quantities of water form solutions having solidifying points sufficiently low so that they may be circulated readily at temperatures of -50 C.

By way of example, a very excellent antifreezing liquid employing potassium acetate may be formed as described in the following example and adhering to the proportions therein stated:

Example I 10 grams of commercial potassium acetate are dissolved in 3 grams of water containing 0.05 gram of anti-pyrine and enough acetic acid to reduce the pH of the solution to'about 8*to 9.-

If desired to buffer this solution, .02 gram of boric acid and .006 gram of potassium hydroxide are added to the solution. To this solution is then added any one of the following materials to reduce wetting power.

(a) 0.15 cc. to 1 cc. raw linseed oil.

(b) 0.3 cc. raw linseed 011 plus 0.3 cc. light petroleum oil of low pour point.

(e) 0.3 cc. lard oil plus 0.3 cc. light petroleum oil of low pour point.

(d) .15 cc. of lard oil,'.15 cc. trichlor benzene and .01 gram gum arabic.

The mixture is preferably then passed through a colloid mill or otherwise thoroughly mixed.

In this example, if the solution is slightly alkaline, for example, with a pH approximately between 8 and 9, the antipyrine or other corrosion inhibitor may be omitted.

This results in the formation of a concentrate which when diluted by adding an equal volume of water will be usable as a circulating medium to temperatures down to 46 C. or lower.

An effective antifreezing liquid may also be made by using potassium formate which acts in a manner very similar to potassium acetate in antifreeze solutions. Potassium formate has the advantage of being somewhat more soluble, in water at ordinary temperature than potassium acetate. A very satisfactory antifreeze liquid using potassium formate may be made according to the following example:

Example II 6.7 grams of slightly alkaline potassium formate is dissolved in 2.6 grams of water and to the resulting solution, 0.03 gram of potassium antimony] tartrate are added. The resulting liquid is then homogenized with .3 cc. of the oils specified in connection with Example I to reduce the wetting power of the resulting liquid. This will make a total volume of about 6.3 ccs. This concentrate can then be made up to a total volume of 10.3 ccs. with water and can be used in a cooling circuit down to a temperature of 50 C.

Even at somewhat lower temperatures, the liquid does not completely solidify.

Sodium acetate and sodium formate may be employed for producing antifreezing solutions having very desirable noncorrosive properties and embodying many of the advantages of the corresponding potassium products, except that 'the solidifying or freezing points of the solutions are somewhat higher and consequently, the corresponding sodium products cannot be used where extremely cold conditions are encountered. Antifreez'ing liquids employing these sodium salts may be made in accordance with the following examples:

. Example III 30 grams of slightly alkaline sodium acetate is dissolved in 100 grams of water containing 1 gram of trlethanolamine. The resulting solution is then homogenized or thoroughly mixed with 3 grams of lard oil. The resulting solution can be satisfactorily used in a cooling system totemperatures as low as 18 C.

Example IV v To a mixture of 25 grams of slightly alkaline sodium formate and 0.7 gram of arsenious oxide "In'th 'caseof-both- Examples III and IV, the liquids formed in accordance-with these examples are ready for use in a cooling circuit without diluting with water.

It will be understood that the foregoing examples are merely illustrative and may be varied considerably without departing from this invention. It should also be borne in mind that commercial alkali metal acetates and formates are often not pure and often contain some water, such as water of crystallization, so that the amount of water added may vary accordingly. It will also be obvious that in .the event that it is not necessary to'employ a solution of reduced wetting power, then the wetting power reducing agent may be omitted, and furthermore, very satisfactory antifreezing preparations can be formed without any corrosion inhibitors. If, for example, the liquid is to be used in contact only with aluminum, the corrosion'inhibitors herein described are unnecessary, providing that the salt solution is only slightly alkaline. It will also be obvious that-mixtures of the salts herein described may be used to produce antifreeze liquids.

Although the acetates and formates are preferably used because of their relatively low cost, the higher fatty acid salts may be used. In spite of expectations to the contrary, the alkali metal salts of some of the higher fatty acids herein mentioned are even more soluble than the salts The antifreezing liquids herein described have a number of advantages in addition to those already stated. These salts do not boil away and repeated boiling down or evaporating of solualone or with the oil for reducing the wetting Y power do not loosen 'old rust in a cooling system. This is a very desirable feature, since otherwise the loosened rust might clog "parts of the system, or leaks may be produced by opening rust clogged holes.

The viscosities at low temperatures of solutions of potassiumacetate and formate at the concentrations necessary are much lower than the viscosities at equal temperatures of glycol or glycerol solutions capable of withstanding the same low temperatures. Consequently, these solutions can be circulated more readily at very low temperatures than corresponding glycerol or glycol solutions. Consequently, potassiumacetate, potassium formate, and potassium proplonate solutions can be used at temperatures materially lower than temperatures at which glycerol or glycol solutions may be used.

An important advantage of my'imprcved anti freeze liquids is that themaximum boiling point,

for example, of potassium acetate solutions is about 165 C. when the solution is boiled down almost to dryness,- and this temperature is below the melting point of soft solder. The boiling point of commercial ethylene glycol is over 200 C., which is above the melting point of soft, solder. The boiling points of my improved antifreeze solutions at the concentrations normally used are only silghtly higher than the boiling point of water. a 4

Further advantages of my improved antifreeze liquids are that they do not affect the finishes ordinarily employed on automobiles and are particularly inert with reference to lacquer finishes, whereas alcohol and glycols attack such finishes. My improved antifreeze solutions also have no effect upon rubber nor upon synthetic resinproducts, such as may be used in gaskets or other parts of cooling systems, and furthermore, my improved liquids donot foam when boiling. The salt solutions herein describedhave the further advantage that they have a higher heat conductivity than glycol or alcohol solutions.

I claim as my invention:

1. The method of cooling metal surfaces which comprises circulating in contact therewith and with cooling surfaces an aqueous solution of high heat conductivity that starts to freeze substantially below 0 C. and can be circulated freely at any temperature above its freezing point; that is stable against oxidation and may be evaporated to dryness without foaming or decomposition or attaining a vapor temperature above 165 C. and the solids of which may then be readily redissolved in water; that will not attack lacquers; that is not substantially more corrosive to iron than ordinary city waterand will not change appreciably in this respect upon repeated concentration and redilution; and that is compatible with common corrosion inhibitors and pH buffering agents, and emulsiflable with common animal, vegetable and mineral oils, containing as a major essential ingredient at least one salt of the group consisting of the alkali metal salts of formic, acetic, ,propionic and butyric acids.

2. In a heat exchange system, an aqueous cooling composition of high heat conductivity that assesses starts to freeze substantially below 0 C. and can be circulated freely at any temperature .above its freezing point: that is stable against oxidation and may be evaporated to dryness without foaming or decomposition or attaining a vapor temperature above 165 C. and the solids of which may then'be readily redissolved in water; that will not attack lacquers; that is not sub-' stantially more corrosive to iron than ordinary city water and will not change appreciably in this respect with repeated concentration and redilution; and that is compatible with common corrosion inhibitors and pH buffering agents and emulsiflable withcommon animal, vegetable and mineral oils, containing as a major essential ingredient at least one salt of the group consisting of the alkali metal salts of formic, acetic, propionic, and butyric acids.

3. A composition which in suitable aqueous dilution produces a medium for heat transfer, to and from metal surfaces, of high heat conductivlty; that starts to freeze below -30 C. and may be circulated freely at any higher temperature; that is stable against oxygen and may be evaporated to dryness without foaming or decomposition or attaining avapor temperature I above 165 C. and the solids of which may then be readily redissolved in water; that will not attack lacquers; that is not substantially more corrosive to common metals than ordinary city water and will not change appreciably in this respect with repeated concentration and redilutiton; and that is compatible with common corr'o'sion inhibitors and 'pH buffering agents and emulsiilable with common -,,animal, vegetable and mineralplls, containing as a major "essential ingredient-a salt of the groupconsisting of the alkali metalsalts oi'.formic, acetic, propionicand butyric acids admixed with a suitable acid in amount sufficient to reduce thealkalinity of'the composition in the dilution in whic h it has" the stated freezing characteristics to a pH of substantially 8 to 9.

4. A composition which in suitable aqueous dilution produces a medium for heat transfer, to and from metal surfaces, of high heat conductivity; that starts to freeze below 30 C. and may be circulated freely at any highertemperature; that is stable against oxygen and may be evaporated to dryness without foaming or decomposition or attaining a vapor temperature above C, and the solids of which may then be readily redissolved in water; that will not attack lacquers; that is not substantially more corrosive to common metals than ordinary city 'water and will not change appreciably in this 'emulsifiable with common animal, vegetable and -mineral oils, containing as a major essential ingredient a salt of the group consisting of the alkali metal salts of formic, acetic, propionic and butyric acids admixed with acid corresponding to the acid radical of said salt in amount sufiicient to reduce the alkalinity of. the composition in the dilution in which it has the stated freezing characteristics to a pH of substantially 8 to 9.

5. A composition which in suitable aqueous dilution produces a medium for heat transfer, to and from metal surfaces, of high heat'conductivity; that starts to freeze below 30 C. and may be circulated freely at any higher temperature; that is stable against oxygen and may be evaporated to dryness without foaming or.de-.

composition or attaining a vapor temperature above 165 C. and the solids of which may then be readily redissolved in water; that will not attack lacquers; that is not substantially more corrosive to iron than ordinary city water and will not change appreciably in this respect with repeated concentration and redilution; and that is compatible with common corrosion inhibitors and emulsifiable with common animal, vegetable and mineral oils, containing as a major essential ingredient at least one salt of the group consisting of the alkali metal salts of formic, acetic, propionic and butyric acids, stabilized by a bufierlng agent of the group consisting of boric acid mixed with its alkali metal salt and alkali metal phosphates.

6. A composition which in suitable aqueous dilution produces a medium for heat transfer, to and from metal surfaces, of high heat conductivity; that starts to freeze below 30 C. and may be circulated freely at any higher temperature; that is stable against oxygen and may be evaporated to dryness without decomposition or attaining a vapor temperature above 165 C. and the solids of which may then be readily redissolved in water; that will not attack lacquers; that is substantially non-corrosive to iron and will not change appreciably in this respect with repeated concentration and redilution; and that is compatible with common pH buffering agents and emulsifiable with common animal, vegetable, and mineral oils, containing as a major essential ingredient at least one salt of the group consisting of the alkali metal salts of formic, acetic, propionic and butyric acids in combination with a corrosion inhibitor of the group consisting of urea, amino acrldine derivatives, arsenious oxide, sodium and potassium chromate, potassium antimonyltartrate and antipyrine.

-7. A composition which in suitable aqueous dilution produces a medium for heat transfer, to and from metal surfaces, of high heat conductivity; that starts to freeze below 30 C. and may be circulated freely at any higher temperature; that is stable against oxygen and may be evaporated to dryness without foaming, decomposition or attaining a vapor temperature above 165 C. and the solids of which may be readily redissolved in water; that will not attack lacquers or loosen existing rust; that is substantially noncorrosive to iron and will not change appreciably in this respect with repeated concentration and redilution; and that is compatible with common pH buffering agents, and will'not creep over metal surfaces, consisting essentially of an emulsion of a solution of at least one salt of the group consisting of the alkali metal salts of formic, acetic, propionic and butyric acids, as a major esential ingredient, with a material of the group consisting of animal, vegetable and mineral oils.

8. A composition which in suitable aqueous dilution produces a medium for heat transfer, to and from metal surfaces, of high heat conducivity; that starts to freeze below -30 C. and may be circulated freely at any higher temperature; that is stable against oxygen and may be evaporated to dryness without foaming, decomposition or attaining a vapor temperature above 165 C. and the solids of which may be readily redissolved in water; that will not attack lacquers or loosen existing rust; that is substantially noncorrosive to iron and will not change appreciably in this respect with repeated concentration and redilution; and that is compatible with common pH buffering agents, and will not creep over metal surfaces, consisting essentially of an emulsion of a solution of at least one salt of the group consisting of the alkali metal salts of formic, acetic, propionic and butyric acids, as a major essential ingredient, with a material of the group consisting of animal, vegetable and mineral oils, these oily materials being mixed with trichlorbenzene in such proportions as to obtain a mixture of the same specific gravity as that of the solution.

9. A composition which in suitable aqueous dilution produces a medium for heat transfer, to and from metal surfaces, .of high heat conductivity; that starts to freeze below 30 C. and may be circulated freely at any higher temperature; that is stable against oxygen and may be evaporated to dryness without foaming or decomposition or attaining a vapor temperature above 165 C. and the solids of which may then be readily redissolved in water; that will not attack lacquers; that is substantially non-corrosive to common metals and will not change appreciably in this respect with repeated concentration and redilution; and that is compatible with common corrosion inhibitors and emulsifiable with common animal, vegetable and mineral oils; containing as a major essential ingredient at least one salt of the group consisting of the alkali metal salts of formic, acetic, propionic and butyric acids admixed with a suitable acid in amount sufficient to reduce the alkalinity of the composition in the dilution in which it has the stated freezing characteristics to a pH of substantially 8 to 9, the pH being stabilized with a pH buffering agent.

10. A composition which in suitable aqueous dilution produces a medium for heat transfer, to

and from metal surfaces, of high heat conductivity; that starts to freeze below -30 C. and may be circulated freely .at any higher temperature; that is stable against oxygen and may be evaporated to dryness without foaming or decomposition or attaining a vapor temperature above 165 C. and the solids of which may then be readily redissolved in water; that will not attack lacquers or loosen existing rust; that is substantially non-corrosive to common metals and will not change appreciably in this respect with repeated concentration and redilution; and that will not readily creep over metal surfaces; consisting essentially of an emulsion of aqueous solution of at least one salt of the group consisting of the alkali metal salts of formic, acetic, propionic and butyric acids, with a minor proportion of an oily material, said emulsion containing a suitable acid in amount sufficient to reduce the alkalinity of the composition in the dilution in which it has the stated freezing characteristics to a pH of substantially 8 to 9, the pH being stabilized with a pH buffering agent.

11. A composition which when dissolved in water to the concentration of substantially 3 pounds of the composition per gallon of solution will produce a medium for heat transfer, to and from metal surfaces, that starts to freeze below 24 C. and maybe circulated freely at any higher temperature; 1 may be evaporated to dryness without foaming or decomposition or attaining a vapor temperature above 165 C. and the solids of which may then be readily redissolved in water; that will not attack lacquers; that is not substantially more corrosive to common metal-s than ordinary city water and will not change appreciably in this respect with repeated concentration and redilution; and that is compat'ible with common corrosion inhibitors and pH buflering agents and emulsiiiable with common animal, vegetable and mineral oils, containing its a major essential ingredient potassium acetate admixed with acetic acid in amount sumclent to reduce the alkalinity of the composition in the stated concentration to a pH 01 substantially 8 to 9.

12. A composition which when dissolved in 7 water to the concentration 'oi', substantially '5 i0.

pounds of the composition .per'gallon of solution will produce a medium for heat transfer, to and from metal surfaces; that starts to freeze below --55-" C. and may be'cir'culated vfreely at any higher temperaturermay be evaporated to dryness withoutioaming or decomposition-or attaining a vapor temperature 1 above 165 'C. and the solids 01' which may then be'readfly redissolved in water; that will not attack lacquers; that is not substantially more corrosive to common metals than ordinary city water and will not change appreciably in this respect with repeated concentration and redilution; and that is compatible with common corrosion inhibitors and pH buffering agents and emulsiflable with common animal, vegetable and mineral oils, containing as a major essential ingredient potassium acetate admixed with acetic acid in amount sumcient to reduce the alkalinity of the composition in the stated concentration to a pH of substantially 8 '13. A liquid composition which will not' without roaming or decomms'ltion or attaining a do; vaporjtemperature above 165 C.- and the solids common animal, 'vegetableand mineral oils, consisting essentially of anaqueous solution of potassium acetate; as.- a;malor essen tial ingredient, having a concentration or sub- .1 grams grams of water containing 0.05 gram of anti- 1 pyrine,1.'02 grams .oi nboric acid reacted with .006 gramoi" potassium hydroxide, .15 to 3:00. of material of the of an emulsifying agent.

.stantially gram of the acetate per 10 cc. of

solution.

14. A liduid composition which when diluted with an equal volume of water will produce a medium for heat transfer, to and from metal surfaces, that starts to freeze below --4 C. and- .-,may be circulated freely 'at any higher temperature: thatiis'stable against oxygen and may be evaporated to dryness without foaming or decomposition or attaining a vapor temperature above 1855C. and the solids of which may then be readilyredissolvedin water; that will not attack lacquers or loosen existing rust; that is substantially non-corrosive to common metals and will not change appreciably in this respect with repeated concentration. or redilution; and that will not creep over metal surfaces,- containing I essentially 10 grams of commercial potassium acetate; 3 grams 01' water. .02 gram of boric acid reacted with .006 gram ofvpotassium hydroxide, .15 to .3 cc. oi material of the group consisting of animal, vegetable and mineral oils, a small quantity of an emulsifying agent and acetic acid in amount sufilcient to reduce the alkalinity of the composition in the stated pH of substantially 8 to 9.

15. A concentrated liquid composition which when diluted with an equal volume of water will produce a medium for heat transfer, to and from final dilution to a metal surfaces; that starts to freeze below 4'C.

and may be circulated freely at any higher temperature: that is stable against oxygen and may beevaporated to dryness without foaming or decomposition or attaining a vapor temperature above 165 c. and the solids of which may then be readily redissolved in water; that will not attack lacquers or loosen existing rust; that is substantiall'y'non-corrosiveto iron and will not q change appreciably in thisrespect with repeated of which may then bereadiiy; redissolved in water; that will notfattack lacquers; that is not substantiallymorecorrosive tog-iron than ordinary city water and will notchange. appreciably in this respect with-repeatedv concentration and 1 redilution; and jthatis compatible with common corrosion inhibitors and pH buffering agents and emulsiflable with concentration or redilution; and that will not creep over metal surfaces; containing essentially commercial potassium acetate, 3

I I group consisting .of animal, vegetablejand mineral-oil and a small quantity DAVID F. sMrrH. 

